There are many different types of containers, tanks, vessels, and canisters that are used for storing fluids. For convenience, this document will use the term “tank” throughout to refer to what could be any kind of container, vessel, canister, tank, or the like.
It is often desirable to allow for monitoring of the fluid level in a tank, particularly in cases where the tank is such that the fluid cannot conveniently be visually inspected. For this reason, many tanks are provided with devices for communicating a fluid level, for example through the use of a fluid-level gauge that can provide an indication of the amount of fluid present in a tank. There are many known examples of fluid level gauges that use a float or a capacitance to mechanically and/or electrically drive an indicator.
It is also desirable in some cases to provide a stop-fill device for preventing a tank from being over-filled. Known stop-fill devices include those intended to be used in tanks that require a fluid to pass through an inlet valve in order to enter the tank. Typically such stop-fill devices include a float that rides on the surface of the fluid in the tank. As fluid is added to the tank, the float rises to a certain level at which point it causes, for example by releasing a spring, the inlet valve to close. Once the inlet valve is closed, no additional fluid can be added to the tank.